
Movable panels on the end of both trunks provide the secret exit for the magician. These are normally held shut by a metal pin inside the wood panels, and are slid open by the magician using a thin knife blade or similar object.
Note that although the ropes are tied around both trunks, they actually do not interfere with the escape in any way. They do, however, provide a great build-up and make the escape seem more impressive. Likewise, using large padlocks and having audience members hold the keys also makes the trick more impressive.
This lesson in magic has been presented courtesy of the Great Mysto!